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BBK & Spacer vs New Rim Offset

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I'm looking to get a K-Sport BBK installed at the front. I'm having a bit of a crisis as the stock wheels (which I like, sue me :p) wont fit them meaning I need a spacer.

However, I dont really want a spacer which means I'd need a new set of rims. I'm worried that the spacer will screw up the handling, but I expect I'm worried over nothing.

If you already have a BBK fitted, could you let me know what ET & width/spacer you are running (along with the rim name?) so I can get a few ideas on sizes that will practically work.

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If you don't go overboard with spacer thickness and tighten properly, they are safe enough and impact on handling is minimal enough to not care much. Impact to handling will be absolutely same if you change wheel/tire offset by spacer or by different offset wheel. Take in mind, that brake clearance doesn't depend just from wheel size and offset, but also from wheel spoke design, and that it can change at different sizes for supposedly same type/model of wheel, and clearance may differ between eg. +30ET wheel with deeper convex spoke design vs +40ET wheel and 10mm spacer. Larger diameter wheels increase chance to clear but it's not given. Same with same type of wheel, where one size clears, but another - doesn't, even if eg. it's of smaller offset.

Take in mind though, that with stock studs you shouldn't use thicker then 3mm slip-on type spacers. If you want thicker ones, consider buying & installing extended length studs (by eg. ARP). Warning about extended length studs though, that it might be problematic replacing them in rears w/o removing wheel hub, but in case of later, it's possible to damage hub bearing. With thickness like 15mm i'd think of maybe bolt-on spacers. 20 and more .. subjectively i wouldn't run, as imho by then increase in eg. scrub radius (heavier steering, a bit more tendency to follow longitudinal road grooves, if it's FWD car, more torque-steer) might start to get noticeable, there might be higher load/wear on hub bearings too. Many run though, deciding that cons are not that high vs their wished goals (of eg. flush fitment and alikes).

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Cheers Church.

The current plan is 20mm bolt on spacers to ensure clearance, that effectively gives a 68 ET on the stock wheels ET of 48.

Pretty sure I got that the wrong way.... it'll have a 28ET effective NOT 68.

It also means the Rim Outer edge is 156mm out from the hub vs 136 stock.

It also means the Rim outer edge is 60mm out from the hub vs 40 stock.

Scrub radius is what has me concerned, and that's why im after the configurations that others currently run, especially those that track the car.

 

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No biggie with mistakes regarding offset. If one forgets what negative or positive means, and that it's offset from centerline, not distance from wheel side, it's easy to confuse, and get it right each time, if extra spacer will rise or reduce it, if bigger or lesser positive or negative offset will actually space them out or in.

Well, effects of scrub radius effects are as i have described. It acts like this: as with different "lever" length (positioned more outward wheel center line from actual wheel turning/pivoting axis) same force gets multiplied, so result is felt as a heavier steering (you have to turn from other end of lever, with more wheel movement per steering wheel movement), and road defects can push/turn wheel a bit more, in case of driven wheels there is more torque steer, as same engine torque can pull wheel more at longer "lever" from turning axis (and how new type-r civic reduced torque steer, by designing front suspension to put wheel turning axis as close to wheel centerline as possible), and with this "longer lever" wheel movements also put more load on bearing.

BUT! Even if it all sounds evil, negative, it's definitely not THAT bad :). So unless you are among those that installed wide body kit and need extra 4-5cm or even more offset change for flushness with new wider width, "reasonable" 5-15mm imho one can easily use w/o much worry, scrub radius effect on RWD car won't be that bad to concern with. If anything, my current smaller diameter aftermarket steering wheel may net similar handling feel change, heavier steering and slightly more felt road defects. Though not for flushness or brake clearance, but in winter i'll be installing 12mm spacers in front, so that with my mods to increase max steering angle for ice drifting wheels don't rub on arch lining and suspension arm. Just take a note regarding studs/spacer types/possible issues. Spacers are often the cheapest way out to increase BBK clearance, even vs purchase of cheap cast wheel set (of design, often not that good for maximizing brake clearance at that).

As for fitment .. this is nice site to check possible result. (won't help with BBK clearance check of course, for which i suggest to d/l from vendor site brake fitment template, glue on carton, cut, and measure actual clearance, "how much spacer" needed. Or try to find on vendor site or in forums about that particular BBK kit, which wheels (and of which size/offset) clear it).

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I can't help you with what size spacers you need, but I have 15mm front and 20mm on the rear (purely for looks, not functionality, bite me) and there is practically no effect on handling. The steering is maybe slightly heavier, but I'm not sure if I can actually feel that, or if it's just a placebo because I know that it should be heavier.

One unintended advantage of spacers - slightly widened track makes negotiating speed cushions a bit easier :D

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